'30 Rock' - TV's best comedy - is only getting better

The season premiere of "30 Rock" finds the sitcom settling into a comfortable, confident maturity in its third year.

Now if only it could break its painful addiction to guest stars.

Yet even there the show is making progress. Megan Mullally pops into the season premiere at 8:30 p.m. today on NBC's WMAQ Channel 5, and none other than Oprah Winfrey visits next week. Neither, however, seizes the spotlight; both serve the needs of the show, not vice versa. In fact, there's a nice little twist to next week's episode that shows Tina Fey's sitcom might just be shaking its addiction, but I don't want to spoil it for loyal viewers.

In any case, tonight's season premiere, "Do-Over," sees the series glorying in its own eccentric, slightly surreal, but dead-on satirical comic universe. Fey, fresh from her triumphant lampoon of Sarah Palin on "Saturday Night Live," returns to her own show - and writes it as well - while starring as Liz Lemon, head writer on a variety show not all that unlike "SNL."

Alec Baldwin, of course, is also back as Jack Donaghy, the self-obsessed network executive you love to hate and hate to love. That might come as a surprise after he lost a corporate power battle to Will Arnett's Devin Banks in last spring's comic cliffhanger, but Baldwin makes it work by returning Jack to his origins serving in the mail room, determined to once again climb his way to the top.

The brilliance of Baldwin's Jack is that while a viewer is trained to hate him as a network exec, he nevertheless makes the role not just sympathetic, but actually gets a viewer rooting for his comeback - even as he resorts to an affair with Devin's sugar-momma wife as a way of getting ahead.

Fey writes him some lovely lines, too, as Jack insists he's ready to work to get his way, because he put himself through Princeton "working the day shift at the graveyard and the graveyard shift at Days Inn."

This is the show at its best, so the guest-star angle, involving Mullally as a bureaucratic social worker trying to screen Lemon's adoption request, actually comes off as quite ancillary. Of course, her interviews with Lemon's co-workers, including Tracy Morgan's Tracy Jordan and Jane Krakowski's Jenna Maroney, go badly, but when she gets conked on the head and suffers amnesia, that gives everyone a second chance, thus the episode title. Even at that, Mullally inserts herself into the ensemble rather than coming in and taking over, and the same goes for Oprah next week, although she's put in a position where she doesn't have to fit in.

Next week is more concerned with the infighting involving Tracy, who has just received a big royalty check for a video game he did, and Jenna, who did one of the voices for the game and got nothing.

"White people stole jazz, rock 'n' roll, Will Smith and heart disease," Tracy says. "Now they think they can take my hard-earned money."

Fey might not have written that line, but her sensibility is all over it. It's wry, edgy, comical, but with a point, and that's "30 Rock" to a tee.

Keep in mind, if "30 Rock" is only getting better, it has already won the Emmy as outstanding comedy for both its previous seasons. It doesn't need to improve.

It also doesn't need big-name guest stars to make it work; it just needs them to attract audience (especially with the rest of NBC's so-called Comedy Night Done Right series struggling). Right now, I'm only hoping for Mullally's social worker to return to put the final kibosh on Lemon's adoption. I'd hate to see "30 Rock" shake its addiction to guest stars, only to jump the shark by saddling her with a baby.

• Ted Cox writes Tuesday and Thursday in L&E and Friday in Sports and Time out!